The new rules, which mirror French and Belgian government guidance, came into force on Monday (4 May).

"From 4 May, passengers must wear a face mask or face covering at our stations and onboard, in line with guidelines announced by the French and Belgian governments," said the rail operator.

"Please ensure you have a mask with you when you travel. Any type of mask is suitable as long as it effectively covers your nose and mouth.

"If you don’t have a mask, you may be refused travel on our services. We’d like to advise you that fines may be imposed in France and Belgium if you’re not wearing a mask."

Meanwhile, Manchester Airports Group – which owns Manchester, Stansted and East Midlands airports – will also ask passengers and staff to wear gloves and cover their faces, according to The Telegraph.

Passengers, the paper reports, will be required to bring their own masks and gloves, although the airports will have some PPE supplies available.

Group chief executive Charlie Cornish said government had been "slow" to consult with the aviation sector on flying once the immediate coronavirus outbreak slows.

He echoed comments made by Heathrow chief executive John Holland-Kaye that social distancing would be ineffective on public transport, while stressing via alternative measures people would soon be able to travel safely by air.

Holland-Kaye has called a set of "common international standards" for air travel to be agreed within a month to assist the recovery of the aviation sector.